This invention relates to a method and apparatus for detecting multiple-feed situations with regard to documents being fed along a transport path, and more particularly, it relates to detecting multiple-feed situations relating to documents having MICR (Magnetic Ink Character Recognition) encoding thereon.
One of the problems associated with prior art, multiple-feed detection systems with regard to the feeding of documents along a transport path is that some of these systems are not able to detect multiple-feed situations in all kinds of overlapping situations of the documents. For example, some systems which attempt to detect multiple-feed situations by measuring the "length" of a document and comparing it with a standard expected length, may miss a multiple-feed situation in which two documents, which are shorter than the expected length, are in slightly overlapping relationship so as to be interpreted by the system as being the expected length or a single document.
Other prior art, multiple-feed detection systems which rely on photo sensors, for example, to detect double thicknesses of documents by light passing through both documents do not operate well when the documents have colors of different color densities thereon.